Coral reefs have managed to bounce back, despite being under constant threat of extinction. However, marine scientists caution these fragile ecosystems are still being threatened by global warming, pollution and human activity.

The discovery of a large number of coral reefs in excellent health has been quite a joyous occasion for the researchers who routinely deal with ominous news like mass die-offs, worldwide bleaching events, oil spills, and such other calamities which have been pushing the coral reefs towards extinction, reportedThe Washington Post.

A decade-long study of remote islands in the Central Pacific has indicated that these coral reefs might survive despite threats posed by global warming brought on by climate change and warming of the oceans due to increasing amounts of carbon dioxide introduced by burning of fossil fuels.

In a large scale study covering 56 islands, researchers studied 450 locations that were once teeming with coral reefs. Researchers looked at regions spanning from Hawaii to American Samoa. They even investigated locations in the remote Line and Phoenix Islands as well as the Mariana Archipelago. To their surprise, they realized there are quite a few locations where coral reefs have defied the odds and bounced back to life. Smith’s report was published recently in the journal Proceedings of the Royal Society B.

The researchers wanted to investigate the impact of climate change as well as a 1998 El Nino event that led to widespread bleaching. Since 1998, coral reefs had been increasingly banishing the symbiotic algae that gave them their brilliant colors and welcoming seaweed, which encroaches on the real estate once occupied by the corals. Study leader Jennifer Smith, a professor at Scripps’ Center for Marine Biodiversity and Conservation said the following.

“After a bleaching event, it really matters what happens to all those dead skeletons. Do they get colonized by big seaweeds, or do they get covered by coralline algae, which are providing settlements for baby corals and providing an environment that facilitates recovery.”

Majority of the reefs that have shown signs of regaining their structure are located near far-flung islands. They are significantly healthier as compared to the reefs near islands that are heavily populated and frequented by humans. In other words, human influence, coupled with coral reef bleaching event — fueled in part by El Niño-driven Ocean warming — has had its detrimental effect on the delicate undersea ecosystem. Such was the impact and scientists had painted a very gloomy picture stating up to 70 percent of coral reefs would vanish before 2050.

It now appears the fear that these reefs were on their way to extinction, has been largely alleviated. The coral reefs that have clearly bounced back strongly indicate that such features won’t fade from existence in the coming decades, as previously feared. Speaking about the discovery of such healthy coral reefs, Smith explained its significance for the researchers.

“There are still coral reefs on this planet that are incredibly healthy and probably look the way they did 1,000 years ago. The scientists were practically in tears when we saw some of these reefs. We’ve never experienced anything like it in our lives. It was an almost religious experience.”

Smith seems justifiably euphoric because just like environmental science, coral-reef researchers have been dealing with dying and degraded ecosystems, which can be a traumatic and rather depressing experience. However, the sight that greeted the researchers is certainly a breath of fresh air, continued Smith.

“It’s hard to fathom. I would jump into the water and there would be so much coral, so many different species of fish, so much complexity and color. I would find myself underwater, shaking my head, looking around in disbelief that these places still existed.”

Though coral reefs occupy less than 0.1 percent of the ocean floor, they shelter close to 25 percent of all marine species, reportsLos Angeles Times. Besides helping oceanic life, coral reefs also offer food, tourism and flood protection to human settlements along the coastline.